Dimpled membranes formed from high density polyethylene (HDPE) are known for dampproofing of foundation walls, such as poured concrete, concrete block, or preserved wood walls. Typically, such a membrane is formed with an array of similar dimples, which are adapted to rest against a foundation wall so as to space the membrane from the foundation, except where the dimples rest against the foundation wall, whereby to provide an air gap serving as a drainage space for moisture entering the air gap from inside or outside the membrane.
Typically, when such a membrane is installed on a foundation wall, polymeric plugs having preformed holes are inserted into selected dimples and steel pins are driven through the plugs via the preformed holes, through the membrane at the dimples having the plugs, into the foundation wall. The plugs are intended to provide seals where the pins are driven through the membrane. It is known for such membranes to be manually installed by workers using hammers to drive the pins.
As described above, dimpled membranes and polymeric plugs for such membranes are available commercially from Big "O" Inc. of Exeter, Ontario, under the "System Platon" designation, and from Casella Dorken Products, Inc. of Beamsville, Ontario, under the "Delta-MS" designation. Steel washers and steel pins are specified by Big "O" Inc. for upper margins of "System Platon" membranes.
In the prior art, an attempt was made to enable a worker to use a fastener-driving tool, such as combustion-powered, fastener-driving tool, by adapting the workpiece-contacting probe illustrated and described in Gupta U.S. Pat. No. 5,484,094 not only to work with steel washers, as disclosed therein, but also to work with polymeric plugs described above. As illustrated and described therein, the probe has two permanent magnets to hold a washer plate with or without a central aperture, as a fastener, such as a steel pin or a wire nail, is driven through the washer plate into a substrate.
In the attempt that was made, a workpiece-contacting probe was provided not only with two permanent magnets adapted to hold a steel washer but also with a collet having several plug-holding fingers intended to hold a polymeric plug. The workpiece-contacting probe had relatively movable elements that were arranged to be manually adjustable between a washer-holding condition, in which the magnets were to be used, and a plug-holding condition, in which the fingers were to be used.
In the attempt that was made, the workpiece-contacting probe proved to be generally unsatisfactory. One problem was that its movable elements tended to become plugged with mud or debris. Another problem was that the fingers did not work satisfactorily over the wide range of dimensional tolerances of the polymeric plugs that were available commercially.